High efficiency vapor control system

ABSTRACT

A vapor control system in which noxious and odoriferous vapors are first condensed and the remaining non-condensable vapors subjected to a scrubbing operation to wash and dilute the residual gases, the scrubbed gases as an incident of their evacuation from the system being subjected to additional treatments selectively utilizing chemical gaseous and incinerating mediums to further purify the effluent so that it is effectively odor free when discharged from the system, the system enabling the user to obtain maximum odor control utilizing the treatment mediums which are most efficient and economical for the operating conditions encountered.

United States Patent 11 1 Dupps, Sr.

1 1 HIGH EFFICIENCY VAPOR CONTROL SYSTEM [75] Inventor: John A. Dupps,Sr., Germantown,

Ohio

[731 Assignee: The Dupps Company, Germantown.

Ohio

[22] Filed: Jan. 23, 1974 [21] Appl. No.: 435,705

[52] US. Cl 55/222; 23/277 C; 23/284; 55/228; 55/233; 55/259; 55/261;261/98;

[51] Int. Cl .1B0ld 47/06 [58] Field of Search 55/222, 227. 228, 233,

1 1 May 13, 1975 Primary E.\'aminer-Bernard Nozick Attorney, Agent, orFirm-Melville, Strasser, Foster & Hoffman 1 1 ABSTRACT A vapor controlsystem in which noxious and odoriferous vapors are first condensed andthe remaining noncondensable vapors subjected to a scrubbing opera tionto wash and di1ute the residual gases, the scrubbed gases as an incidentof their evacuation from the system being subjected to additionaltreatments selectively utilizing chemical gaseous and incineratingmediums to further purify the effluent so that it is effectively odorfree when discharged from the system, the system enabling the user toobtain maximum odor control utilizing the treatment mediums which aremost efficient and economical for the operating conditions encountered.

7 Claims, 7 Drawing Figures HIGH EFFICIENCY VAPOR CONTROL SYSTEMBACKGROUND OF THE INVENTION This invention relates to pollution controlapparatus and has to do more particularly with improvements in the typeof vapor control apparatus disclosed in US. Pat. No. 3,572,010, issuedMar. 23, l97l, and entitled Vapor Control Apparatus." In accordance withthis patent, contaminated vapors, such as those generated in therendering of animal, fish and poultry by-products to yield fat andtankage, are processed in a vapor control tower which condenses thegenerated vapors, washes the remaining noncondensables to removeobjectionable odors, and additionally serves to evacuate odor laden airfrom the building in which the apparatus is located, thereby alsoeffectively controlling odors which are inevitably released within theprocessing plant itself. While such vapor control apparatus has beenhighly effective in controlling objectionable vapors, the present daydemands for ecological improvements has dictated even more stringentcontrols than were heretofore deemed satisfactory.

Accordingly, the present invention is directed to improved vapor controlapparatus in the form of a system which is highly efficient and, in thecase of the effluent from a rendering plant, is capable of removing inexcess of 99% of the objectionable odors prior to discharge into theatmosphere.

RESUME OF THE INVENTION In accordance with the invention, the vapors tobe treated are first subjected to an initial treatment in which they arecondensed, the condensate removed, and the remaining non-condensablespassed through a water spray which washes and dilutes the remaininggases. Such initial treatment is of known character, although as will bepointed out hereinafter, whereas the washing or scrubbing operation washeretofore performed utilizing water as the washing medium, the presentinvention contemplates the admixture of chemicals utilized in asecondary treatment with the wash water to enhance the washingefficiency.

A principal feature of the present invention is the treatment of thewashed gases in the vapor control tower, such gases as an incident oftheir evacuation from the system being subjected to one or more chemicaltreatments utilizing liquid and gaseous mediums, together with theremoval of condensate, so that the discharged effluent is essentiallyfree from pollutants. In an alternative arrangement, only the odor ladenplant air is subjected to the washing and chemical treatments in thevapor control tower, the noncondensables removed from the bottom of thetower housing being scrubbed in a separate scrubber which utilizes thechemical containing washing solution from the tower as the scrubbingmedium, the washed gases from the separate scrubber being dischargedinto an incinerator wherein the residual gases are burned. Thisarrangement provides the user with alternative procedures which may beselectively utilized depending upon the economics involved, which willvary depending upon the nature and extent of contamination of the vaporsbeing treated and the relative costs of the chemicals and fuel for theincinerator. Under conditions wherein the noxious odors to be removedare not extreme, the chemical treatment of the non-condensables in thetower normally will be the more efficient and economical. However, inother instances, it has been found to be more efficient to chemicallytreat only the plant air in the tower, which requires far less chemicalsthan if the non-condensables are also treated, the noncondensables beingsubjected to an initial washing operation in a separate scrubber,whereupon the residual gases are incinerated. Such alternativearrangement is particularly suited to situations wherein the vaporsbeing treated require massive chemical treatment to remove objectionableodors and/or where an incinerating means, such as a plant boiler, isreadily available to incinerate the residual gases as a secondaryfunction, or where the cost of incineration is less than the cost of thechemicals required to treat the noncondcnsables in the tower.

The invention contemplates a tower construction in which the variousoperating components for treating the vapors are contained within anelongated, vertically disposed, and preferably cylindrical tower, thevapors to be treated entering the system toward the upper part of thetower, traveling downwardly for condensation, with condensate removal atthe bottom of the tower, whereupon contaminated plant air is drawn intothe tower, with or without the non-condensables, to create an air streamtraveling upwardly through the tower for scrubbing and chemicaltreatment, Such arrangement requires a relatively small amount ofvaluable floor space in the plant and, in addition, provides for maximumefficiency in the utilization of treatment materials. Thus, the initialtreatment basically utilizes water as the treating medium, with the moreexpensive chemical treating mediums concentrated in the after orsecondary treatment portion of the tower wherein the gases being actedupon have already been relieved of a substantial portion of theircontaminants. Conse quently, the required chemical materials only needbe supplied in a quantity sufficient to remove the residualcontaminants. In addition, the residual liquid chemicals from the aftertreatment flow downwardly through the housing where they are mixed withthe wash water and utilized to enhance the effectiveness of the washingoperation performed as a part of the initial treatment, irrespective ofwhether such initial treatment is conducted in the tower or in aseparate scrubber. The system is highly efficient, not only in theremoval of contaminants from the vapors being treated, but also in theutilization of treatment materials, leading to over-all reductions inoperating costs.

DESCRIPTION OF THE DRAWINGS FIG. 1 is a pictorial vertical sectionalview of a vapor control tower in accordance with the invention.

FIG. 2 is a vertical sectional view taken along the lines 22 of FIG. 1.

FIG. 3 is a vertical sectional view taken along the line 3-3 of FIG. 1.

FIG. 4 is a vertical sectional view taken along the line 44 of FIG. 1.

FIG. 5 is a vertical sectional view taken along the line 55 of FIG. 1.

FIG. 6 is a vertical sectional view taken along the line line 66 of FIG.1.

FIG. 7 is a fragmentary elevational view with parts broken awayillustrating the use of a separate scrubber and incinerator fornon-condensables removed from the tower.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring first to FIG. 1 of thedrawing, the tower apparatus comprises an elongated, verticallydisposed, and preferably cylindrical housing 1 having a lower or initialtreatment zone A, and an upper or secondary treatment zone B. Vapors tobe treated enter the sys tem through the vapor inlet conduit 2 at theupper end of the primary treatment zone, and gases which are treated andpurified in the tower are discharged from the top of the tower throughexhaust stack 3 the extension of which projects upwardly through theroof of the building in which the vapor control apparatus is located soas to vent the decontaminated gases to the outside atmosphere. it willbe understood that a suitable fan, indicated diagrammatically at 4, islocated within or operatively connected to the exhaust stack to draw thetreated gaseous residue and air upwardly through the housing 1. Air isintroduced into the system through inlet ports 5 in the annular base 6at the bottom of the housing, the lowermost portion of which is dividedby a baffle 7 into a reservoir 8 and a condensate discharge compartment8a.

The vapor inlet conduit 2, through which the vapors and non-condensablesare introduced into the system, extends inwardly through the wall ofhousing 1 with its innermost end opening into a closed upper chamber 9,preferably of annular configuration and a diameter sufficiently smallerthan the diameter of the housing 1 so as to provide an essentiallyannular passageway 10 for the gases and air which are drawn upwardlythrough the housing for subsequent discharge. An annular bank ofcondensing tubes 11 extends downwardly from the upper chamber 9, theuppermost ends of the tubes 11 opening into the undersurface of thechamber 9, such openings being indicated at 12. At their lowermost ends,the condensing tubes 11 open into a closed lower chamber 13, which isalso of annular configuration and extends inwardly from the wallsurfaces of housing 1, the lower chamber terminating inwardly in anannular wall 14 defining an airflow passageway 15 through which air andnon-condensables flow upwardly within the housing.

A vertically disposed spray pipe 16 extends upwardly through the centerof the housing from the reservoir 8 to the area of upper chamber 9, thespray pipe being closed at its opposite ends and equipped at spacedintervals along its length with radially disposed sets of spray nozzles17 arranged to direct conical sprays of water outwardly from the spraypipe onto the annular array of condensing tubes 11, the sprayed wateralso passing beyond the condensing tubes out to the wall surfaces of thehousing 1. The water returns to the reservoir by gravity, running downthe tubes and the walls of the housing into the reservoir 8 through thepassage 15. Thus, the water sprayed from the nozzles 17 will cool thecondensing tubes and hence condense the vapors flowing through thetubes, the condensate soforrned being collected in the lower chamber 13from which the condensate is discharged into discharge chamber 8athrough drain conduit 18. The collected condensate, together withoverflow from reservoir 8, is discharged from the system throughdischarge conduit 19 which may be connected to a sewer or other disposalmeans.

Waterfor the spray pipe 16 is supplied from reservoir 8, pump means 20being arranged to withdraw water from the reservoir through outlet pipe21 for introduction into the bottom end of spray pipe 16 through inletpipe 22. The spray water is in part recirculating in that the returningwater which runs down the condensing tubes will return to the reservoir,although preferably a portion of the returning water will spill into thedischarge compartment 8a and will be discharged along with thecondensate. Such arrangement prevents the build-up of excessive saltsand also serves to further cool the condensate prior to its dischargeinto the sewer. The reservoir will also be provided with a supply offresh water, through a suitable inlet pipe and floatcontrolled valvemechanism (not shown), which will serve to automatically add makeupwater to the reser voir when the apparatus is in use. If desired, theheight of the water in the reservoir may be controlled to permit some ofthe water from the reservoir to cascade into the discharge compartment8a, or the baffle 7 may be perforated for such purpose, thereby furtherfacili tating the discharge of the condensate.

Along with the condensate, the lower chamber 13 also collects thenon-condensable gases which are withdrawn through conduit 23 by blower24 which directs the non-condensables through conduit 25 forintroduction through conduit 26 into the annular base 6 of the housingin the area above the reservoir 8 where the gases are drawn upwardlythrough annular passage 15 along with plant air drawn into the housingthrough the inlet ports 5. in the event incineration of the noncondensables is desired, the valve 27 will be utilized to divert thegases through conduit 28 to the separate scrubbing and incineratingmeans which will be described hereinafter.

When the non-condensable gases are returned to the tower through theannular base 6, they are admixed with the plant air drawn into thesystem through inlet ports 5 and are thus highly diluted. As the airstream so-formed is drawn upwardly through the housing, it will flowoutwardly between the annular array of condensing tubes 11 and aroundthe upper chamber 9 through the annular passage 10. During such flow,the air stream is washed by the water being sprayed from the nozzles 17,such spraying action serving to remove particulate matter carried by theair stream; and the air stream in turn acts to remove heat from thesystem and discharge it into the atmosphere.

The tower apparatus thus far described is of known character and hasheretofore been utilized in the con trol of noxious and odoriferousvapors. While such apparatus will remove up to about 60% of theobjectionable contaminants encountered in the vapor effluent from arendering plant which was wholly adequate under heretofore customaryemission control standards many communities now require much higher standards. It has been found that even the most stringent standards can bemet by subjecting the air stream to one or more chemical treatments,which can be conveniently conducted within the housing 1 immediatelyabove the upper chamber 9. However, in the event the cost of thechemical treatment becomes excessive when the entire operation isperformed in the tower, the system may include a separate scrubber andincinerator for the non-condensables withdrawn from the chamber 15.

In accordance with the invention, provision is made in the tower forchemically treating the partially puri fied air stream. While chemicaltreatments have heretofore been utilized in vapor control systems, theuse of a chemical after treatment in conjunction with an initialtreatment of the character described, provides a number of advantages.Since a substantial portion of the objectionable materials are removedduring the initial treatment, substantial economics can be effected inmany instances in the quantity of the treating materials required forthe after treatment; and the treating materials can be selected inaccordance with the specific nature of the impurities remaining in theair stream. In addition, by conducting the chemical treatment in theupper portion of the tower, the chemicals, after performing theirinitial treatment function, may be reused, in part at least, to enhancethe scrubbing of the air stream which takes place during the initialtreatment. whether such initial treatment takes place in whole or inpart within the tower. Such reuse of the chemicals effects furthersavings in two ways; first, a saving is effected by the mere fact thatthe materials are being reused, and second, by reuse in conjunction withthe ini tial treatment, the chemical additives enhance the effectivenessof the scrubbing operation and hence the air stream contains lessimpurities at the time it is subjected to the secondary treatment, withthe result that less chemicals are required to complete the purificationof the effluent gases.

Referring again to FIG. 1, the after treatment area of the systemcomprises a perforated support or base 29 overlying the upper chamber 9and occupying the entire inside dimensions of the housing 1. As seen inFIG. 2, the base 29 comprises an annular frame having spaced apartsupporting ribs, such as the ribs 30, supported on a medial transversemember 31. The support is surfaced with a perforated material 32, whichmay conveniently comprise one or more sections of expanded metal havinga relatively large open flow area. Preferably the base 29, which mayhave a diameter on the order of 10 feet, will be formed in sectionswhich can be readily removed and reinstalled, thereby facilitatingcleaning and maintenance.

The base 29 serves as a support for a bank of packing rings 33, seen inFIGS. 1 and 3, which provide a massive reactive surface area forexposing the air stream to the chemicals. The packing rings are of knownconstruction and generally comprise cylindrical members having spacedapart openings in their cylindrical wall surfaces and interconnectinginternal webs arranged in spider-like fashion. Such rings, which areusually formed from plastic or ceramic materials, are designed toprovide maximum surface area while minimizing resistance to airflowthrough and around the rings. Thus, when the rings are wetted with aliquid substance, they effectively provide maximum exposure of theliquid to the air stream. In accordance with the invention, a bank ofpacking rings will be built-up on support 29. While illustrated insideby-side and stacked relation, the rings are often in randompositions, as dumped on the base 29 and leveled. In an exemplaryembodiment wherein the housing has a diameter of 10 feet, the bank ofpacking rings will be from 3 to 4 feet deep.

Spray means 34 overlie the bank of packing rings, the spray means havinga plurality of spaced apart spray heads 35 arranged to direct conicalsprays of the chemicals downwardly on the bank of packing rings. Anexemplary arrangement of such spray heads is illustrated in FIG. 4, theprimary objective being to insure full coverage of the packing ringswith the chemicals. The air stream, as it travels upwardly through theafter treatment section of the housing, is exposed both to the chemicalcarrying surfaces of the packing rings and also to the conical spraysthemselves, thereby assuring optimum exposure of the air stream to thechemical treatment.

Essentially, the selection of the chemical treatment will depend uponthe composition of the air stream and the odors to be removed. Wherevapors from a rendering plant are being processed, solutions of causticsoda, sodium hypochlorite, and potassium permanganate may be employed,as well as other chemical compounds having the desired purification anddeodorizing properties.

A moisture filter or demister 36 overlies the spray means 34 and servesthe dual function of containment of the sprayed chemicals and removal ofmoisture from the air stream. As seen in FIG. 5, the demister comprisesa suitable frame 37 which supports a batting 38 of metal excelsior,preferably about 6 inches in thickness, through which the air streamflows prior to discharge. Moisture in the air stream condenses on themetal strands and drains downwardly, ultimately returning to thereservoir 8.

The after treatment section may also include a gas diffuser, indicatedat 39. preferably located in the re duced diameter exhaust stack 3justbeyond the demister 36. The diffuser illustrated is of the type having afluted rotary impeller contained within a diffusion chamber having anannular discharge orifice, indicated at 40, the unit being mountedwithin the exhaust stack 3 by means of supporting arms 41, as possiblybest seen in FIG. 6. One or more supply conduits, such as the conduits42 and 43 are arranged to supply one or more desired gases to thediffuser which discharges the gaseous medium into the air stream as itflows upwardly through the exhaust stack and around the diffuser.

The gas treatment is optionai but may be utilized as a further means forpurifying and deodorizing the air stream. Thus, the air stream may beselectively treated with ozone, chlorine, or other purifying anddeodorizing gases in controlled amounts, or with mixtures of gases. Thegas diffuser may take other forms, inclusive of the use of an array ofdischarge nozzles arranged to admix the discharged gases with theoutgoing air stream.

While the tower apparatus just described is highly ef ficient and isdesigned to minimize the consumption of chemicals in the after treatmentsection, the cost of the chemicals can nonetheless be quite substantial,or in short supply a condition which is not uncommon in the currentmarket. Accordingly, the present invention provides certain alternativeswhich may be utilized to effect still further economies under certainoperating conditions. Thus, as seen in FIG. 7, the conduit 28 may beutilized to divert the non-condensables to a scrubber 44 wherein theyare subjected to the action of a spray head 45, the non-condensablegases being drawn upwardly through the scrubber by means of the blowerunit 46. In accordance with the invention. the spray head 45 is suppliedwith washing liquid from the vapor control tower. Thus, washing liquidmay be piped directly from the spray pipe 16 in the tower by means ofconduit 47. Of course, if desired, the spray head 45 may be suppliedfrom an independent source, but preferably it will utilize the washingsolution in the tower, thereby taking advantage of the chemicals whichare introduced into the system during the after treatment.

Since a primary function of the scrubber 44 is to reduce chemicalconsumption in the tower, particularly where massive amounts ofchemicals would be required to deodorize noncondensable gases having ahigh odor level, it should be readily evident that with the diversion ofthe non-condensables to the scrubber 44, and hence with only plant airflowing upwardly through the tower for chemical treatment, the quantityof chemicals required will be materially reduced. However, even undersuch conditions, effective amounts of the chemicals remain in thewashing solution which returns to the reservoir to enhance the sprayingaction which takes place in the scrubber, although in this instance theeffluent gases will be incinerated rather than discharged directly intothe atmosphere.

Provision is made, however, for metering additional chemicals to thespray head 45 in the scrubber if such expedient is deemed necessary. Thechemicals will be supplied to the spray means 34 in the tower throughconduit 48, being pumped from the chemical tank 49 through conduit 50 bymeans of pump 51. Suitable metering controls 52 are provided to controlthe flow of the chemicals to the tower spray means 34. Chemicals fromthe tank 49 may also be supplied to the spray head 45 in the separatescrubber through branch conduit 53 and metering and mixing valve 54interposed in the conduit 47 which supplies washing solution underpressure from the spray pipe 16 in the tower. While the primary functionof the scrubber 44 is to remove solids from the non-condensable gasesprior to incineration, the chemical treatment in the scrubber may beutilized as a means to combat odors which are not effectively eliminatedby incineration.

Washing solution and particulate matter from the scrubber may bedischarged into the sewer system through drain 55, with the gases drawnupwardly through the scrubber by the blower unit 46 discharged throughduct 56 which delivers the scrubbed gases to an incinerator 57 for otherburner unit wherein they are incinerated. While a separate incineratormay be utilized, it is sometimes possible for the user to take advantageof an existing burner, such as a plant furnace or boiler, to incineratethe gases, thereby effecting still further economies in the operation ofthe system.

As should now be evident, vapor control apparatus in accordance with theinvention provides an integrated system capable of achievingsubstantially complete removal of contaminants. The system provides theuser with the ability to vary the treatment in accordance with thenature of the noxious or odoriferous gases encountered, and at the sametime the system is highly efficient, with the effluent from the aftertreatment utilized to enhance the effectiveness of the initial scrubbingoperation whether such operation be performed in the tower or in theseparate scrubber. The user also has the ability to vary the treatmentin accordance with the availability and cost of necessary chemicals, aswell as the availability and relative cost of operation of theincinerating means.

Modifications may be made in the invention without departing from itsspirit and purpose. Various such modifications have already been setforth and others will undoubtedly occur to the skilled worker in the artupon reading this specification. Consequently, it is not intended thatthe scope of the invention be limited other than in the manner set forthin the claims which follow.

The embodiments of the invention in which an exclusive property orprivilege is claimed are defined as follows:

l. A vapor control system comprising an elongated, vertically disposedtubular housing having air inlet means at its bottom and air dischargemeans at its top, including blower means connected to said housing forcreating an air stream flowing upwardly through said housing; a lowertreatment zone comprising upper and lower spaced apart annular chambersmounted in said housing, an annular passage between said housing andsaid upper chamber, said lower chamber terminating inwardly in anannular wall defining a centrally disposed air flow passage, the saidair stream flowing upwardly through the said passages, an annular arrayof condensing tubes interconnecting said upper and lower chambers andsurrounding the air flow passage in the lower chamber, means forintroducing odor containing vapors into said upper chamber, means forwithdrawing condensate from said lower chamber, means for withdrawingnon-condensables from said lower chamber, conduit means connected to themeans for withdrawing noncondensables from said lower chamber and to thehousing for introducing the non-condensables into the air stream beneathsaid lower chamber, and first spray means in said housing positioned tospray liquid onto said annular array of condensing tubes through the airstream; an upper treatment zone in said housing overlying said upperchamber comprising means for subjecting the air stream to a liquidchemical treatment, and means overlying the said liquid chemicaltreatment means for thereafter removing moisture from the air streamprior to its discharge from the system through said air discharge means;a reservoir underlying said lower annular chamber for collecting bothresidual liquid chemicals from the chemical treatment means and liquiddischarged by said first spray means for recirculation, and conduitmeans, including pump means, connected to said reservoir and to saidfirst spray means for pumping admixed liquid and chemicals from saidreservoir to said first spray means; and a separate scrubber adjacentsaid housing, spray means in said scrubber, conduit means operativelyconnecting the spray means in said scrubber to the reservoir in saidhousing, metering means for introducing additional chemicals into theconduit supplying the spray means in said scrubber, said metering meansbeing connected to said last named conduit and to a separate source ofliquid chemicals, means connected to the means for withdrawingnon-condensables from the lower chamber for diverting thenon-condensables to said scrubber for passage therethrough, and meansfor withdrawing the noncondensables for said scrubber for delivery to anincinerating means.

2. The vapor control system claimed in claim 1 wherein the means forremoving moisture from said air stream comprises a batting of metalexcelsior overlying said spray means.

3. The vapor control system claimed in claim I including gas diffusingmeans overlying the means for removing moisture from said air stream,whereby the air stream may be treated with a gaseous medium immediatelyprior to its discharge from the system.

4. The vapor control system claimed in claim 3 wherein said gasdiffusing means includes means for selectively introducing differentgaseous mediums into the air stream and for alternately blendingdifferent gases for discharge into the air stream.

5. The vapor control system claimed in claim 1 wherein said liquidchemical treatment means includes packing means presenting a largesurface area exposed to the air stream. and second spray means forspraying the packing means with liquid chemicals.

1. A VAPOR CONTROL SYSTEM COMPRISING AN ELONGATED, VERTICALLY DISPOSEDTUBULAR HOUSING HAVING AIR INLET MEANS AT ITS BOTTOM AND AIR DISCHARGEMEANS AT ITS TOP, INCLUDING BLOWER MEANS CONNECTED TO SAID HOUSING FORCREATING AN AIR STREAM FLOWING UPWARDLY THROUGH SAID HOUSING; A LOWERTREATMENT ZONE COMPRISING UPPER AND LOWER SPACED APART ANNULAR CHAMBERSMOUNTED IN SAID HOUSING, AN ANNULAR PASSAGE BETWEEN SAID HOUSING ANDSAID UPPER CHAMBER, SAID LOWER CHAMBER TERMINATING INWARDLY IN ANANNULAR WALL DEFINING A CENTRALLY DISPOSED AIR FLOW PASSAGE, THE SAIDAIR STREAM FLOWING UPWARDLY THROUGH THE SAID PASSAGES, AN ANNULAR ARRAYOF CONDENSING TUBES INTERCONNECTING SAID UPPER AND LOWER CHAMBERS ANDSURROUNDING THE AIR FLOW PASSAGE IN THE LOWER CHAMBER, MEANS FORINTRODUCING ODOR CONTAINING VAPORS INTO SAID UPPER CHAMBER, MEANS FORWITHDRAWING CONDENSATE FROM SAID LOWER CHAMBER, MEANS FOR WITHDRAWINGNON-CONDENSATE FROM SAID LOWER CHAMBER, CONDUI! MEANS CONNECTED TO THEMEANS FOR WITHDRAWING NONCONDENSABLES FROM SAID LOWER CHAMBER AND TO THEHOUSING FOR INTRODUCING THE NON-CONDENSABLES INTO THE AIR STREAM BENEATHSAID LOWER CHAMBER, AND FIRST SPRAY MEANS IN SAID HOUSING POSITIONED TOSPRAY LIQUID ONTO SAID ANNULAR ARRAY OF CONDENSING TUBES THROUGH THE AIRSTREAM; AN UPPER TREATMENT ZONE IN SAID HOUSING OVERLYING SAID UPPERCHAMBER COMPRISING MEANS FOR SUBJECTING THE AIR STREAM TO A LIQUIDCHEMICAL TREATMENT, AND MEANS OVERLYING THE SAID LIQUID CHEMICALTREATMENT MEANS FOR THEREAFTER REMOVING MOISTURE FROM THE AIR STREAMPRIOR TO ITS DISCHARGE FROM THE SYSTEM THROUGH SAID AIR DISCHARGE MEANS;A RESERVOIR UNDERLYING SAID LOWER ANNULAR CHAMBER FOR COLLECTING BOTHRESIDUAL LIQUID CHEMICALS FROM THE CHEMICAL TREATMENT MEANS AND LIQUIDDISCHARGED BY SAID FIRST SPRAY MEANS FOR RECIRCYALTION, AND CONDUITMEANS, INCLUDING PUMP MEANS, CONNECTED TO SAID RESERVOIR AND TO SAIDFIRST SPRAY MEANS FOR PUMPING ADMIXED LIQUID AND CHEMICALS FROM SAIDRESERVOIR TO SAID FIRST SPRAY MEANS; AND A SEPARATE SCRUBBER ADJACENTSAID HOUSING, SPRAY MEANS IN SAID SCRUBBER, CONDUIT MEANS OPERATIVELYCONNECTING THE SPRAY MEANS IN SAID SCRUBBER TO THE RESERVOIR IN SAIDHOUSING, METERING MEANS FOR INTRODUCING ADDITIONAL CHEMICALS INTO THECONDUIT SUPPLYING THE SPRAY MEANS IN SAID SCRUBBER, SAID METERING MEANSBEING CONNECTED TO SAID LAST NAMED CONDUIT AND TO A SEPARATE SOURCE OFLIQUID CHEMICALS, MEANS CONNECTED TO THE MEANS FOR WITHDRAWINGNON-CONDENSABLES FROM THE LOWER CHAMBER FOR DIVERTING THENON-CONDENSABLES TO SAID SCRUBBER FOR PASSAGE THERETHROUGH, AND MEANSFOR WITHDRAWING THE NON-CONDENSABLES FOR SAID SCRUBBER FOR DELIVERY TOAN INCINERATING MEANS.
 2. The vapor control system claimed in claim 1wherein the means for removing moisture from said air stream comprises abatting of metal excelsior overlying said spray means.
 3. The vaporcontrol system claimed in claim 1 including gas diffusing meansoverlying the means for removing moisture from said air stream, wherebythe air stream may be treated with a gaseous medium immediately prior toits discharge from the system.
 4. The vapor control system claimed inclaim 3 wherein said gas diffusing means includes means for selectivelyintroducing different gaseous mediums into the air stream and foralternately blending different gases for discharge into the air stream.5. The vapor control system claimed in claim 1 wherein said liquidchemical treatment means includes packing means presenting a largesurface area exposed to the air stream, and second spray means forspraying the packing means with liquid chemicals.
 6. The vapor controlsystem claimed in claim 5 wherein said packing means comprises a bank ofpacking rings seated on a perforated support plate.
 7. The vapor controlsystem claimed in claim 6 wherein said second spray means comprises aplurality of spray heads overlying said bank of packing rings andpositioned to spray liquid chemicals downwardly onto said packing ringsand the upwardly flowing air stream.